While my last PID controller build is extremely versatile and a multi-tasker, the only drawback is that it requires AC power to operate. I recently put together an Ugly Drum Smoker, which unlike my CharGriller, is (somewhat) portable. The need came up for me to build a PID + blower fan rig that could be powered from AC, but also portable power if necessary. Luckily for me, the JLD612 comes in a 12 volt model, and with a background in car electronics, this 12-volt setup was a cake walk. This particular build is not a multi-tasker, just a straight up smoker controller.

While at home, I can power it with a standard 12 volt wall wart power supply, and when on the go, I can use a jump pack, or even a car battery and some alligator clips.

Just like anything I post, this is the way *I* built this unit. Is it the only way to do it? Nope. Is it the absolute best? Probably not. But it works for me, and should give you, the reader, enough information to help you figure out something on your own.

Completed unit

Parts List

Here are the parts I used for my build – many have “See Power Input Notes below” because you can pick and choose whatever type of physical input power connector you wish.. this is just what I ended up with myself. There are infinite choices, many better ones than I have used, you’re free to do what you wish.

Various quick disconnect crimp connectors. If you have a well stocked electrical connector box for automotive stuff, that will get you through it

Hot glue gun to mount components like the barrier strips

Dremel tool / drill, to mount everything in the box

Power Input Notes

I chose to use a wall wart for my 12 volt power source (when AC is available), and also put an on/off switch for the whole unit. You don’t need to use either, but you can if you want. I actually bought the wall wart, but, if you go digging in your junk pile at your residence, you will probably find a 12V power supply that works just fine for you from an old phone or router. You may also decide to use this away from any type of power source ever, and just use a 12 Volt battery or jump starting pack (my whole reason for building a 12 volt PID in the first place) – in that case, pick whatever type of physical power input plug works for you. Digikey and Radio Shack have extensive choices, have fun with their catalogs.

Relay Talk

The JLD612 has two different methods of activating the heating device, in our case, a blower fan. It can use the built-in relay J2, or it can use the built in SSR (solid state relay) control. Since I had relays laying around, my build uses the J2 option. If you want to use an SSR, by all means, go right ahead. Sample units are here and here. The advantage of using an SSR is that you could use the built in alarm functions of the JLD612 to activate warning lights (anything, really) on low or high temperature conditions, while using the SSR output for the PID control. In my setup, J2 is tied up with PID control, so only J1 is available for alarm output.

Fan Output – Rectangle in to a round hole?

When I first envisioned this thing, my only real question without having the parts in my hand was if the rectangular output of the fan would mate up to the circular hose barb – more importantly, if I would have to block off the air from the fan exit so that it would only blow out of the hose barb, and not just blow inside the project box. The answer is, no, I did not have to block off any of the fan exit. When I mounted everything, I lined it up as best I could, and plenty of air comes out of the barb without any sort of special ductwork. I am actually impressed at the amount of air that this fan moves.

Component Mounting

I mounted the JLD612 and thermocouple jack first. Make templates with cardboard for the JLD612 and thermocouple panel jack. Transfer these templates to the plastic project box and start cutting. My JLD612 is mounted high on the box as far as I can go, while still being able to attach the wire terminals for pins 6-10 on the JLD612, and leaves enough space for the fan to fit in the box.

Closeup of fan mounting post

Once the JLD612 is in place, I worked on mounting the hose barb, which is the fan output. I first placed the fan in the box and mounted it as high as I could without interfering with the JLD612, but also clearing the plastic ridge inside the box. I then marked its two mounting holes and drilled holes in the plastic box. Using a 2″ M4 machine screw, I secured the screw through the box, with a nut on the inside. I then added 1 nut to each screw, so the fan stood off of the box by about a 1/4″ (eyeballed). Once the fan was mounted, I marked the center location of the fan output, and drilled the hole for the hose barb. Mount the hose barb with the conduit nuts, then adjust the location of the fan so that it is centered in the host barb opening. Once it’s centered, add another nut to each screw to hold the fan securely.

Mounting hole for JLD612. Posts for the fan, and barb mounted.

The switch, warning light, and power input jack all mount through drilled holes. The relay inside mounts on one of the fan screw posts with a nut, just so it’s not bouncing around.

Wiring

Input voltage comes in through the M connector. Negative (aka ground in the 12V world) goes straight to the Negative Barrier Strip. +12v goes through the switch, to the fuse holder, then to the +12V Barrier Strip.

Supply +12V from barrier strip to the JLD612 on pins 1, 4*, 13, and the relay pin 30

Connect the red pin of your thermocouple to pin 8 of the JLD612 (through panel jack)

Connect each blue pin of your thermocouple to pin 9 and 10 of the JLD612 (through panel jack)

Connect pin 14 of the JLD612 to pin 86 of the relay

Connect pin 87 of the relay to the fan positive input

Connect pin 5 of the JLD612 to your warning light +12v*

*Warning light not pictured at the time of writing this

Everything mounted and wired

That’s about it as far as construction goes! You will want to familiarize yourself with the PID controller manual and set all of the configuration parameters properly on the first use. My settings are as follows on the ‘0089’ set menu: